BLUEMOMENT

My state-of-the-art ST50 log has a temperature function - I think it's so you know when you are in currents like the Aghulas. On Saturday morning it showed over 20C in Loch Goil and I have heard of higher in Loch Fyne at Inverary. The weed on my boat is certainly more rampant than usual.

Yep, I've seen 20+ consistently on the west coast - warmer outside of the Clyde. There's a marine heatwave apparently. I don't think this is a good thing.

I've seen 18-20c on the temp recorded by my speed/depth/temp through hull gizmo......but not after I calibrated it

I can do 8.5knts now I recalibrated mine . . .

As for the temp - I wonder if the very top layer of water is quite a bit warmer due to the sun heating it up. So what the ST60 sees isn't a real measure of much.

16.3 Celsius, Firth of Lorne, 2 miles east of Loch Spelve, at the moment. Yesterday, further south is was 17 celcius. Brand new Raymarine transducer for ST60 speed. High water temperature can be indicative of a failing sensor. Prior to the previous sensor failing it was reading over 30 Celsius.

Just to add, when the temperature sensor goes, so does the speed, it just stops reading speed.

https://seatemperature.info/scotland-wa ... ature.html

From earlier in the year https://www.metoffice.gov.uk/blog/2025/ ... e-heatwave